Process for recovering lithium from lithium-sulfur accumulators

Abstract

The invention relates to a process for recovering lithium from lithium-sulfur accumulators, wherein the accumulators are discharged, shredded, and pre-cleaned by sieves or screens to separate housing and electricity collector parts, the remaining material is dispersed in an aqueous medium, resulting in formation of a lithium sulfide containing solution from which insoluble components are removed by filtration, and the electrolyte is removed by phase separation, followed by a process for separation of the lithium from the lithium sulfide-containing solution.

Claims

1. A process for recovering lithium from discharged lithium-sulfur rechargeable batteries comprising housing parts, current collector parts, and electrolyte, wherein the discharged lithium-sulfur rechargeable batteries are shredded and precleaned by sifting or sieving for separation of the housing parts and the current collector parts, characterized in that remaining material comprising the lithium and the electrolyte is dispersed in an aqueous medium with a pH≥7, resulting in formation of a lithium sulfide-containing solution from which insoluble components are removed by filtration, and the electrolyte is removed by phase separation, followed by a process for separation of the lithium from the lithium sulfide-containing solution.

2. The process according to claim 1, characterized in that the separation of the lithium from the lithium sulfide-containing solution is carried out by thermal processing.

3. The process according to claim 2, characterized in that the thermal processing is carried out in a temperature range from 100 to 1500° C. in the presence of oxygen.

4. The process according to claim 2, characterized in that the thermal processing is carried out in a temperature range from 100 to 1500° C. with exclusion of oxygen.

5. The process according to claim 1, characterized in that the separation of the lithium from the lithium sulfide-containing solution is carried out by chemical oxidation.

6. The process according to claim 5, characterized in that the chemical oxidation is carried out by reaction with hydrogen peroxide, ozone or hydroxyl radicals.

7. The process according to claim 1, characterized in that the separation of the lithium from the lithium sulfide-containing solution is carried out under acidic conditions.

8. The process according to claim 7, characterized in that the acidic conditions are produced by adding sulfuric acid or hydrochloric acid to the lithium sulfide-containing solution, the lithium obtained is converted into the corresponding salts, and the formed polysulfur compounds are separated by extraction.

9. The process according to claim 1, characterized in that the separation of the lithium from the lithium sulfide-containing solution is carried out by precipitation.

10. The process according to claim 9, characterized in that the precipitation of the lithium from the lithium sulfide-containing solution is carried out by the addition of water-soluble carbonates to the lithium sulfide-containing solution.

Description

EXAMPLE 1

(1) Thermal Processing of a Lithium Sulfide-Containing Solution at 200° C.

(2) An aqueous lithium sulfide-containing solution with an Li content of approximately 3% by weight was heated in an oven with circulating air at a heating rate of 10 K/min, wherein min is used as an abbreviation for minute, to 200° C. After reaching the target temperature, the sample was kept for 1 h at the target temperature under continuous air flow. The waste gas was removed via a gas scrubber filled with alkaline washing solution. By means of a phase analysis by X-ray diffractometry (XRD), the solid was identified as lithium hydroxide. The isolated yield was 91%.

EXAMPLE 2

(3) Thermal Processing of a Lithium Sulfide-Containing Solution at 500° C.

(4) An aqueous lithium sulfide-containing solution with an Li content of approximately 3% by weight was heated in an oven with circulating air at a heating rate of 5 K/min to 500° C. After reaching the target temperature, the sample was kept for 1 h at the target temperature under a continuous air flow. The waste gas was removed via a gas scrubber filled with alkaline washing solution. The main phase of the residue consisted of lithium hydroxide, and 3 LiOH x Li.sub.2SO.sub.4 was identified as secondary phase by X-ray diffractometry. The isolated yield was 77%.

EXAMPLE 3

(5) Obtention of Li.sub.2SO.sub.4 from a Lithium Sulfide-Containing Solution by Chemical Oxidation

(6) 20 g of an aqueous lithium sulfide-containing solution with an Li content of approximately 3% by weight were cooled to 0° C. in a temperature-controlled glass reactor. Under constant stirring, 40 g of a half-concentrated hydrogen peroxide solution (15% by weight) were added to the cold solution within 20 min. Due to the strongly exothermic reaction, a temperature rise to 60° C. was observed. After 1 hour of stirring, the solution was reduced and dried until the weight was constant. By means of a phase analysis by X-ray diffractometry, the solid was identified as lithium sulfate, which was present in the form of both Li.sub.2SO.sub.4 and Li.sub.2SO.sub.4 x H.sub.2O. The isolated yield was 91%.

EXAMPLE 4

(7) Obtention of Li.sub.2CO.sub.3 from a Lithium Sulfide-Containing Solution by Carbonate Precipitation

(8) 20 g of an aqueous lithium sulfide-containing solution with an Li content of approximately 3% by weight were placed in a reactor. Under constant stirring, the lithium-containing solution was mixed with 11.5 g sodium carbonate. The suspension obtained was centrifuged, and the sediment was dried at 80° C. until the weight was constant. By means of a phase analysis by X-ray diffractometry, the solid was identified as lithium carbonate. The isolated yield was 92%.

EXAMPLE 5

(9) Obtention of LiCl from a Lithium Sulfide-Containing Solution by Acidic Processing

(10) 20 g of an aqueous lithium sulfide-containing solution with an Li content of approximately 3% by weight were placed in a temperature-controlled reactor. The reactor was equipped with a distillation unit and with a dosing unit. Via a waste gas line, a gas scrubber with aqueous alkaline washing solution was connected. Under constant stirring, 21.2 g of half-concentrated hydrochloric acid (15% by weight) were metered in within 10 minutes via a dosing system. The mixture was reduced to dryness, and the product was dried until the weight was constant.

(11) By means of a phase analysis by X-ray diffractometry, the solid obtained was identified as lithium chloride, which was present in the form of both LiCl and LiCl x H.sub.2O. The isolated yield was 84%.